So been running 5100s for a while now, at first they rode great but now, after a year i can feel every bump in road. Checked everything, tire pressure is at 30 psi, uca are clear and everything is installed properly. However in the rear, one of the shocks appears to be leaking oil. I noticed an oily substance on the shock body today. I only have a 1" rear block, but is it possible I over extended the shock? Could this be the cause for the rough ride? thanks

If it turns out to be your shock, Bilstein does off a limited lifetime warranty if you have the original receipt. They probably would only send you one if you qualify, but I'd buy a new one for the other side to keep them the same age.
http://www.bilsteinus.com/index.php?id=949